<!DOCTYPE html>
<html lang="zh_CN">
<head>
    <meta charset="UTF-8">
    <title>常用标签</title>
</head>
<body>
   <div>有换行效果，表示文档节点（白纸，没效果）</div>
   <span>不换行干净标签<br/></span>
   <span>不换行干净标签（br表示换行）</span>
</body>
</html>